Hydraulic oil aerating in diff/trans

[grizzley30814]

Hello all,
Quick question for you gurus. I have a 1300D, runs great but has a loud knock that is a little troubling. I have changed the oil and filter on the motor. Running 15-40 in the motor. I don't believe the knock is from the crank or rods. I believe it is coming from the hydraulic pump. the fluid in the rear diff/trans is white/aerated. At first I thought it might have been water but if you put some on your fingers it will clear out and is just oil. I have a 155d manual but it isn't clear. where is the screen / filter for the hydraulics? I am going to check the screen, clean it and change the fluid and see it it gets any better/quieter. Any other ideas would be welcome also.

 

[winston1]

HYD SCREEN RUBBER GROMMET: Yanmar Tractor Parts (screen location)

I believe you also have a rubber sleeve coupling on the suction line going to your pump. Make sure it is not sucking air at that point.

 

[rScotty]

Hello all,
Quick question for you gurus. I have a 1300D, runs great but has a loud knock that is a little troubling. I have changed the oil and filter on the motor. Running 15-40 in the motor. I don't believe the knock is from the crank or rods. I believe it is coming from the hydraulic pump. the fluid in the rear diff/trans is white/aerated. At first I thought it might have been water but if you put some on your fingers it will clear out and is just oil. I have a 155d manual but it isn't clear. where is the screen / filter for the hydraulics? I am going to check the screen, clean it and change the fluid and see it it gets any better/quieter. Any other ideas would be welcome also.

If it's not leaking oil under the far side -right side- of the tractor, then in that model it's more common to have water in the transmission fluid than air. Particularly if left outside. Water enters past the shifter.

No, they don't tell you very clearly where that cleanable filter lives. If you go to the Yanmar Tractor Parts location that Winston has given you in post #2, you will see a pipe held to flange with three bolts. Now look under your right foot on the tractor - under the floor board. Look for something held on with 3 bolts to the transmission case. That's where that pipe lives, and the filter comes out when you loosen and remove that pipe from the transmission housing. Remove the 3 bolts. BTW, all the hydraulic fluid will come out at the same time if you haven't drained it yet.

Move the pipe & flange - you may have to loosen the other end of the pipe which is where Winston mentions a rubber sleeve coupling. Make sure that rubber sleeve coupling isn't split and the source of an air leak! Order a new one anyway. Now reach in the transmission and pull the filter out. If it has stringy white on it that's water. Gently clean the filter in gasoline or with soap and water.. It's basically either nylon or wire mesh about #200 mesh size.... a 2" diameter tube of mesh maybe 8 to 10 inches long with a projection on each end to fit the rubber donuts that hold the filter into place, When installing, it's easy to get it situated wrong and squash the filter. If you do, just pull it out, strighten it out and reinstall. The YM135 takes 2.5 quarts of hydraulic fluid - although some just use motor oil. The radiator takes a 50/50 mix of antifreeze & water.
luck,
rScotty

 

[CoyPatton]

Hello all,
Quick question for you gurus. I have a 1300D, runs great but has a loud knock that is a little troubling. I have changed the oil and filter on the motor. Running 15-40 in the motor. I don't believe the knock is from the crank or rods. I believe it is coming from the hydraulic pump. the fluid in the rear diff/trans is white/aerated. At first I thought it might have been water but if you put some on your fingers it will clear out and is just oil. I have a 155d manual but it isn't clear. where is the screen / filter for the hydraulics? I am going to check the screen, clean it and change the fluid and see it it gets any better/quieter. Any other ideas would be welcome also.

You say it is not water in the fluid. Your reasoning is that with some fluid on your finger it clears out and is just oily.

I feel the need to remind you that unless agitated water and petroleum products will separate, both on your finger and in the transmission housing.
You should be able to determine this as you drain the fluid by watching closely as it drains. Mostly likely the water will drain first assuming the tractor has sat for a bit before draining.
And as rScotty said, you will drain the fluid (or at least most of it regardless) when you remove the screen. I much prefer the easier to control drain opening than the 2” or so opening from the screen housing. I also think your problem is most likely to be a water issue. One other way to check this before draining is to run the tractor long enough that friction (only real source to heat up hydraulic fluid) will heat up the fluid, if air pressure has build up in the housing, as you open up your dipstick fill port, you might hear a rush of air as the seal is broken. This is a maybe because you could have enough venting to allow air to escape. You could also insert a long clean dip stick to check for ‘milky’ slimy fluid.
Good luck

 

[careyo63]

It was the last of the fluid in my YM2000 that was milky as could be. Down right thick and nasty. It was in there for awhile that's for sure. Looking at the screen I wondered if it was ever changed. The screen showed to be what was allot of pressure damage. Pinched in half basically. I replaced it! Not the first problem since. Over 12 twelve yrs. And still going. Not that far from rolling the tac. I was under 100 when l bought it. 075 when l changed the fluid so it won't be long. Honestly l hardly use my Hyd. much if I have the rear scoop on is about it. So I believe your do for sev. and your be good. Take care of these tractors and they're pretty much trouble free. Esp the old basic Ym series.

 

[CoyPatton]

It was the last of the fluid in my YM2000 that was milky as could be. Down right thick and nasty. It was in there for awhile that's for sure. Looking at the screen I wondered if it was ever changed. The screen showed to be what was allot of pressure damage. Pinched in half basically. I replaced it! Not the first problem since. Over 12 twelve yrs. And still going. Not that far from rolling the tac. I was under 100 when l bought it. 075 when l changed the fluid so it won't be long. Honestly l hardly use my Hyd. much if I have the rear scoop on is about it. So I believe your do for sev. and your be good. Take care of these tractors and they're pretty much trouble free. Esp the old basic Ym series.

You don’t use your Hyd. much.
This is a common misconception that if you don’t use the 3ph or have a FEL or other such items you are not using the hydraulic fluid.
But you need to think what you are using every time your tractor moves! You have a common fluid for the transmission, PTO, 3 ph, loader...
you only have a few fluids on the entire machine (fuel, coolant, oil and hydraulic fluid). You use each every time you start the tractor! Your hydraulic pump runs off the engine do it is flowing

 

[careyo63]

My 3pt. Lift is the only thing my Hyd. Pump uses. I'm Gear driven. I may lift the FM. Every now and then. No loader. Used a 50hp. JD. wiih a Frontier Fel. and know it's capability all to well. Haven't, won't and don't even consider one for the little YM2000. Here's the JD. 5103 used it for about 10 yrs..

 

[CoyPatton]

My 3pt. Lift is the only thing my Hyd. Pump uses. I'm Gear driven. I may lift the FM. Every now and then. No loader. Used a 50hp. JD. wiih a Frontier Fel. and know it's capability all to well. Haven't, won't and don't even consider one for the little YM2000. Here's the JD. 5103 used it for about 10 yrs..

Your gear drive transmission is not a dry transmission else there would not be seals on the rear drive axle or PTO shaft. So while pressure may inly he required by lifting your 3ph, it is far from the only thing using that fluid. And the pump runs while the engine runs.
Please quit promoting false information to others who may not have knowledge to recognize misinformation. While the gears in your transmission may be more of splash bath, it still uses the fluid!
Otherwise why dies a differential or transfer case in a truck have fluid?

 

[California]

....The YM135 takes 2.5 quarts of hydraulic fluid - although some just use motor oil.

Quarts, or gallons? The slightly larger Yanmars take most of a five gallon pail.

 

[rScotty]

Quarts, or gallons? The slightly larger Yanmars take most of a five gallon pail.

Yikes! Good catch. That's wrong info. I should have said 2.5 gallons (10 quarts). Wonder how/if I can change or edit it??

The actual amount is more like ten quarts. See below.
Thanks,
rScotty